At present, the degree of compaction is the main criterion for subgrade compaction quality, is the relative expression of the compacted density. Just average, does not adequately reflect the subgrade compaction layer vertical compaction density distribution law. Compaction boundary layer micro-unit compression pressure on in the process of pressure transmission decreases gradually until they reach the critical formation pressure dense layer. Compaction by detecting the boundary layer vertical zone layer densification, to calculate the boundary thickness, to draw isodense of densification, a clear reproduction of the compacted layer vertical compaction density distribution law. This paper describes the detection principle, functional structure and System Design of vehicle automatic detection system used to detect compaction boundary layer of each vertical zone.
This paper mainly studies the wall mounted high safe micro control system. The use of a new control system make the safe is safer, more reliable. The safe has built-in microcomputer control chip PIC16F877A, realizes the password control, automatic lock, an indoor alarming and monitoring network and a series of functions, the thief can not start. The apparatus is convenient for household use, and is convenient for residential property and Public Security Bureau network monitoring, has great social benefit and development foreground.
Susceptibility level of low-dropout regulator (LDO) is measured based on direct power injection (DPI) method in this paper. Hardware and software of standard DPI test bench is set up with test flow and algorithm being optimized. Extraction of injection power is analyzed, and impedance simulation validates the test which is carried by vector network analyzer (VNA). A test chip of Elmer2 which is dedicated to EMC study is used for DPI measurements. The failure mechanism of LDO module in Elmer2 is studied under EMI. On-chip sensor is also used for interested nodes voltage extraction with probability and statistical methods, susceptibility level is further found out with on-chip measurements. After comparison with traditional test method, this technique has optimized DPI method which can develop the applications of susceptibility measurements for complex devices.
Aiming at the characteristics of transfer function for 30mm+300mm asymmetrical chord offset method and by further research of its amplitude-frequency and phase-frequency, it states that the wave length for the track irregularity which can be restored by this method ranges from 30mm to 1320mm. Through filtering the wave length of the original and restored statistics, the maximum error of this restoration method can be controlled within 10%, which verifies the accuracy and reliability of this method. And it also provides theoretical reference for the application of this restoration method in track irregularity.
the thesis briefly describes the historical background of flame retardant, overviews the function mechanism of flame retardant, generally reviews the current situation of flame retardant industrial development both abroad and at home, then points out the great gaps existed in the flame retardants production such as the product variety and product quality between china and developed countries. On this basis, defines the developing characteristics, the opportunities and facing-challenges for the global flame retardant industrial development, combines with the research direction and developing trends of Chinese flame retardants, gives up some rationalization recommendations for the industrial production of flame retardants in china.
An improved adaptive iterative learning algorithm is applied on manipulators with repetitive time-varying disturbance. The saturation function was used when designed control law to reduce the torque chattering problem, and to force the manipulators to track time-varying reference signal fast, correctly and with assigned speed. The effectiveness of the proposed control system is demonstrated by Lyapunov analysis and simulation results: when the number of iteration increase, the tracking error will converge to zero uniformly with respect to the finite time interval, and chattering phenomenon reduced.
Organic light emitting devices (OLED) with the structure of ITO/TPD/Alq(3)/ZnO/Al were prepared by vacuum thermal evaporation method. By establishing multi-layer structure model, we discussed the influence of Alq(3) deposition thickness and ZnO buffer layer on the photoelectric performance of the device, got the relationship of current density and work voltage. The results show that ZnO buffer layer can produce additional dipole energy and reduce the electronic potential barrier of cathode, its best thickness is 3 nm, too thin or too thick will increase the driving voltage, block carriers injected. When the thickness of Alq(3) film is 50 nm, the photoelectric performance is best, current density reaches 100 mA/cm(2), the increase of Alq(3) thickness will make the electronics through the layer become scarce, affect the compound with holes. The results provide theoretical guidance to optimize the design and increase the performance of OLED.
Bamboos are tall, perennial, arborescent grasses, belonging to the Bambusae, a tribe under Graminae. Recently, bamboo fiber is developed to produce different textile products in China. By using of the Weibull theory, the relationship between the breaking strength and testing gauge length of the bamboo fibre which was extracted by the chemical and carded processes was investigated in this paper. The results show that the estimator (2a) is more acceptable than the other three estimators for predicting the fibre breaking strength. Weibull theory can be used to predict the breaking strength at a longer gauge length accurately but can not be used to predict the bamboo strength at a shorter gauge length.
FACTS (Flexible AC Transmission Systems) that can rapidly control the active power, reactive power and voltage of transmission line, is becoming one of the study focus. But at the same time, some difficulties have been occurred in power flow calculation with FACTS devices. In this paper, the modeling and algorithms for power flow calculation of power system with FACTS devices are classified, the recent research results are summarized, and the features, applications and deficiencies of various algorithms and models are analyzed. Finally, this paper makes discussions on further study in choice of state variables, selection of initial value and exceeding constraint of control variables, and analyses the direction of research on power flow calculation with FACTS.
In order to promote the practical application of IEC61850 in status monitoring (SM) system of smart substation, combined with the function requirement of smart substation SM and the characteristics of SF6 circuit breaker state on-line monitoring, the model for actual intelligent electronic device (IED) of SF6 circuit breaker SM is established in terms of the information modeling technology of IEC61850, which is described in substation configuration description language (SCL). Besides, this paper analyses the buffered report control block, file transfer model and their service. A communication method between SM intelligent electronic devices is proposed which the SM data is mapped to GOOSE message to transfer, at last the software processing of GOOSE message is analyzed in detail.
Automobile clutch cover assembly performance testing machine is an equipment used for testing the integrated capability of automobile clutch. C-type head and slider mechanism are the important parts of the testing machine. Their quality relates to the whole machine to test clutch pass or fail. These 3-D solid models of C-type head and slider mechanism of the testing machine are built by 3-D design software PRO/ENGINEER. Then they are conducted modal analysis by importing into software ANSYS to determine the natural frequencies and modes, so it makes structural design avoid resonance. The result also provides the basis and reference value to further structural optimization design.
Researches relevant to the characteristics of water flow and river-bed variation in a river bend has been of very importance in river evolution by now. With the help of transition curve often using in the design of transportation routine, a experiment flume was designed by inserting transition curve between a straight flume and a circle curve flume, 24 run's of movable bed experiments for different bend types and bed material and discharge and flow time were carried out respectively. By analyzing the data obtained from 24 runs experiments, the effect of reducing erosion of the flume with transition curve were investigated. As the results, the transition curve flume has a better effect in decreasing the scour of the current and to the river bed and dike and the feet of dike than circle bend.
Based on image processing technology, a non-contact liquid level measuring system is designed. Its consists of three parts: a COMS camera, three laser light sources, and a PC. The work principle of the device is that the laser beams from the laser source is irradiated to the liquid at a certain angle, and the image of the tank's interior is picked up by the CMOS camera, then the light spots on the liquid surface is extracted by the technology of image processing, through the triangle area of the three light spots, the information about liquid-level can be obtained. The model of the measurement system is proposed in the paper, and the method of the calibration is given by using the least square algorithm. Experiment tests that the liquid level measuring method is reliable and stable.
In order to extract sensitive bearing friction torque defect feature, come up with a new method based on the EMD and Hilbert Envelope Spectrum. According to bearing friction torque signal, EMD decomposition is used to get the IMF components, then Hilbert Envelope Spectrum analysis is conducted in the bigger correlation coefficient of the IMF components. By analyzing the sensitive bearing outer and inner ring signals, it shows that this combination method is effective to extract sensitive bearing manufacturing defect feature.
The intermediate point's temperature and the intermediate point's enthalpy are used as the characterization to control temperature of steam and feed water on supercritical boiler. Relative to the control of intermediate point's temperature, the control of intermediate point's enthalpy is more sensitive. Now, mechanism modeling is difficult to apply to supercritical boiler. The system identification which is modeling by the information providing by input and output data is superior. According to the DCS data, building and simplifying a mathematical model by using the MATLAB system identification. Finally making use of a simulation example shows the effectiveness of the model.
At present, cluster tools processing 450mm wafer are increasing used in modern semiconductor wafer fabrication facilities. The little batch sizes and mix-wafer processing bring out more transient behavior in 450mm wafer manufacturing. This paper presents the transient model of parallel and serial cluster tools respectively. The model is helpful to understand the transient behavior and evaluate the cycle time.
Base on the i¶Guideline for the Certification of Wind Turbinesi·, this paper describes the problem of bolt fatigue broken and its mechanical behaviors under an alternating load. In order to solve the problem and to find a regulation, various types of bolt will be parametric and set up in ANSYS. The software can help to simulate the process of loading and to get the stress concentration factor and fatigue notch factor, which are closely relevant to a bolt fatigue life. Finally, structure's S/N curve will be got through calculating. From the research, bolt's diameter, preload, the material of component can be considered as influence factors. This paper is helpful for calculating bolt's fatigue life with FEM model and is a valuable engineering application.
A design idea and realizing way for J2EE oral test system based on J2EE is put forward to supplant traditional one-to-one test form between examiner and examinee. The paper first deals with the oral test system which includes the test paper formulating subsystem, test subsystem, test marking and result statistics system and the release subsystem, then elaborates on such key technical issues in computerized oral test system as the test Automatic control, safety guarantee, fast distribution of test questions and the construction of oral test private cloud, a reliable multicast scheme can be applied to improve internet efficiency, and in the final the paper gives an introduction of practical effects and imperfection of the system.
A small-scale medical cyclotron has been developing in Huazhong University of Science and Technology (HUST). The RF system mainly consists of a 10kW RF power generator and resonance cavity. Aiming at compact and robust structure, the resonance cavity adopts non-uniform characteristic impedance coaxial structure, and the magnet surface electroplated copper will be used as dummy Dees. The precise shapes and dimensions of cavity are designed and simulation results are carried out in this paper. The distributions of electromagnetic field are illustrated by means of numerical calculation analysis, and fine tuning devices are designed to realize frequency compensation as well. The RF power fed-in system is considered comprehensively with Dee-electrodes which all are settled in vacuum chamber, and the premise design of it has been preceded in this paper. In addition, the wooden model test is preformed before actual machining, and the test results are properly well compared with ideal FDTD calculation results.
This paper described a parallel mild hybrid system with start-stop function, discussed its advantage in the automotive fuel economy and emissions. The functions and principles of mild hybrid system and the idle start-stop system control strategy were expounded. Through the analysis of the mild hybrid system's main parameters, power components and other matching accessories parameters were selected according to production requirements. And then, a mild hybrid test vehicle was produced combined with the power structure scheme and control strategy. The experiment data showed the fuel efficiency of the new system.
